Measures of dispersion Quiz

1. A set has $n=10$, $\sum x=50$ and $\sum x^2=290$. Find the standard deviation.

• A. $4$
• B. $29$
• C. $2$
• D. $\sqrt{29}$

2. Data have standard deviation 1.5 and are coded as $y=4x-3$. Find the standard deviation of $y$.

• A. $3$
• B. $6$
• C. $9$
• D. $36$

3. Which of these is least affected by an extreme value?

• A. Interquartile range
• B. Range
• C. Standard deviation
• D. Variance

4. Find the interquartile range of 1, 3, 4, 6, 7, 9, 10, 12, 13, 15, 16, 18.

• A. $17$
• B. $11$
• C. $10$
• D. $9$

5. A frequency table has $\sum f=20$, $\sum fx^2=1000$ and $\bar x=6$. Find the variance.

• A. $50$
• B. $14$
• C. $44$
• D. $\sqrt{14}$